Method for producing ar(alk)yluraciles, novel corresponding intermediate products and method for producing said intermediate products.
The invention relates to a novel process for preparing ar(alk)yluracils, which are known as herbicidally active compounds, to novel intermediates for this purpose and to processes for their preparation.
It is known that certain substituted cyanophenyluracils can be prepared by reacting appropriate aminoalkenoic esters with appropriate cyanophenyl isocyanates or cyanophenylurethanes in the presence of reaction auxiliaries, such as, for example, sodium hydride (cf. EP-A-648749). However, in this procedure, the yield and the quality of the resulting products are not always entirely satisfactory and the reaction components which are required are not particularly suitable for industrial purposes.
Furthermore, it is known that certain substituted phenyluracils can be prepared by reacting appropriate substituted N-phenylaminoalkenamides with suitable carbonic acid derivatives (cf. WO-A-95/32952). However, the synthesis route described in this publication involves many steps and is complicated.
Furthermore, it is known that substituted cyanophenyluracils are obtained by reacting appropriate cyanophenylpyrimidinones with bases and reacting the substituted N-cyanophenyl-aminoalkenamides formed with carbonic acid derivatives, such as, for example, phosgene or diphenyl carbonate (cf. DE-A-19604582). However, the desired products are not always obtained in high yields and in satisfactory quality.
The invention provides
(a) a process for preparing ar(alk)yluracils of the general formula (I) 
in which
A represents a single bond or represents alkanediyl,
Ar represents optionally substituted aryl,
R1 represents optionally substituted alkyl and
R2 represents hydrogen, halogen or alkyl,
characterized in that substituted aminoalkenamides of the general formulae (IIa) or (IIb) 
in which
A, Ar, R1 and R2 are as defined above
are heated at temperatures between 40xc2x0 C. and 120xc2x0 C., if appropriate in the presence of a diluent,
(b) novel substituted aminoalkenamides of the general formulae (IIa) or (IIb) 
in which
A represents a single bond or represents alkanediyl,
Ar represents optionally substituted aryl,
R1 represents optionally substituted alkyl and
R2 represents hydrogen, halogen or alkyl,
(c) a process for preparing substituted aminoalkenamides of the general formula (IIa), characterized in that substituted pyrimidones of the general formula (III) 
in which
A, Ar, R1 and R2 are as defined above
are reacted at temperatures between 0xc2x0 C. and 100xc2x0 C. with an acid, if appropriate in the presence of a diluent,
(d) a process for preparing substituted aminoalkenamides of the general formula (IIb), characterized in that substituted oxazinones of the general formula (IV) 
in which
R1 and R2 are as defined above
are reacted with ar(alk)ylamines of the general formula (V)
H2Nxe2x80x94Axe2x80x94Arxe2x80x83xe2x80x83(V)
in which
A and Ar are as defined above
at temperatures between 0xc2x0 C. and 150xc2x0 C., if appropriate in the presence of a diluent,
(c) novel substituted pyrimidones of the general formula (III) 
in which
A represents a single bond or represents alkanediyl,
Ar represents optionally substituted aryl,
R1 represents optionally substituted alkyl and
R2 represents hydrogen, halogen or alkyl,
(f) a process for preparing substituted pyrimidones of the general formula (III), characterized in that substituted aminoalkenamides of the general formula (VI) 
in which
A, Ar, R1 and R2 are as defined above
are reacted with dichloromethylene-dimethylimmonium chloride of the formula (VII)
xe2x80x83Cl2Cxe2x95x90N(CH3)2Clxe2x80x83xe2x80x83(VII)
at temperatures between 0xc2x0 C. and 100xc2x0 C. in the presence of a diluent.
The invention also provides the novel route for preparing ar(alk)yluracils of the general formula (I) which involves the steps set forth in a general manner above under (f), (c) and (a).
It is surprising that the ar(alk)yluracils of the general formula (I) can be prepared in a simple manner in high yields and good quality by this novel route.
The oxazinones of the general formula (IV), which are to be used, if appropriate, as intermediates are known and/or can be prepared by processes known per se (cf. Bull. Soc. Chim. Belg. 101 (1992), 313-321; Preparation Examples).
The substituted aminoalkenamides of the general formula (VI) to be used, if appropriate, as intermediates are known and/or can be prepared by processes known per se (cf. DE-A-19604582; Preparation Examples).
Preferred meanings in the formulae (I), (IIa), (IIb), (III) and (VI) are
A represents a single bond or represents straight-chain or branched alkanediyl having 1 to 4 carbon atoms,
Ar represents phenyl or naphthyl, each of which is optionally substituted by amino, cyano, halogen or the grouping xe2x80x94N(R3)SO2R4,
R1 represents optionally fluorine- and or chlorine-substituted alkyl having 1 to 4 carbon atoms,
R2 represents hydrogen, fluorine, chlorine, bromine or alkyl having 1 to 4 carbon atoms,
R3 represents hydrogen or represents in each case optionally fluorine- and/or chlorine-substituted alkyl, alkylcarbonyl or alkylsulphonyl having in each case 1 to 6 carbon atoms in the alkyl groups, represents in each case optionally fluorine- and/or chlorine-substituted cycloalkylcarbonyl or cycloalkylsulphonyl having in each case 3 to 6 carbon atoms in the cycloalkyl groups, or represents in each case optionally fluorine- and/or chlorine-substituted phenylcarbonyl or phenylsulphonyl, and
R4 represents optionally fluorine- and/or chlorine-substituted alkyl having 1 to 6 carbon atoms, represents optionally fluorine- and/or chlorine-substituted cycloalkyl having 3 to 6 carbon atoms, or represents in each case optionally fluorine- and/or chlorine-substituted phenyl.
Particularly preferred meanings in the formulae (I), (IIa), (IIb), (III) and (IV) are
A represents a single bond or represents a methylene group,
Ar represents phenyl which is optionally substituted by amino, cyano, fluorine, chlorine, bromine or the grouping xe2x80x94N(R3)SO2R4,
R1 represents in each case optionally fluorine- and or chlorine-substituted methyl or ethyl,
R2 represents hydrogen, fluorine, chlorine, bromine, methyl or ethyl,
R3 represents hydrogen or represents in each case optionally fluorine- and/or chlorine-substituted methyl, ethyl, n- or i-propyl, acetyl, propionyl, methylsulphonyl or ethylsulphonyl, represents in each case optionally fluorine- and/or chlorine-substituted cyclopropylcarbonyl, cyclobutylcarbonyl, cyclopentylcarbonyl, cyclohexylcarbonyl, cyclopropylsulphonyl, cyclobutylsulphonyl, cyclopentylsulphonyl or cyclohexylsulphonyl, or represents in each case optionally fluorine- and/or chlorine-substituted phenylcarbonyl or phenylsulphonyl, and
R4 represents in each case optionally fluorine- and/or chlorine-substituted methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, represents in each case optionally fluorine- and/or chlorine-substituted cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, or represents in each case optionally fluorine- and/or chlorine-substituted phenyl.
The abovementioned general or preferred radical definitions apply both to the end products of the formula (I) and, correspondingly, to the starting materials or intermediates required in each case for the preparation. These radical definitions can be combined with one another at will, i.e. including combinations between the given preferred ranges.
The processes according to the invention described above under (a), (c), (d) and (f) are abbreviated below as xe2x80x9cprocess (a)xe2x80x9d, xe2x80x9cprocess (c)xe2x80x9d, xe2x80x9cprocess (d)xe2x80x9d and xe2x80x9cprocess (e)xe2x80x9d.
Using, for example, N-(4-cyano-2,5-difluoro-phenyl)-3-amino-4,4,4-trifluoro-2-butenamide and dichloromethylene-dimethylimmonium chloride as starting materials, reacting the product obtained in their reaction according to process (f), for example, with hydrogen bromide according to process (c) and heating the resulting product according to process (a), the course of the reaction can be illustrated by the following formula scheme: 
The process (f) according to the invention for preparing compounds of the general formula (III) is carried out using a diluent. Suitable diluents for this purpose are, especially, inert organic solvents. These include, in particular, aliphatic, alicyclic or aromatic, optionally halogenated hydrocarbons, such as, for example, benzine, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, petroleum ether, hexane, cyclohexene, dichloromethane, chloroform, carbon tetrachloride; ethers, such as diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran or ethylene glycol dimethyl ether or ethylene glycol diethyl ether; ketones, such as acetone, butanone or methyl isobutyl ketone; carboxylic acids, such as acetic acid or propionic acid, nitriles, such as acetonitrile, propionitrile or butyronitrile; esters, such as methyl acetate or ethyl acetate amides, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-formanilide, N-methyl-pyrrolidone or hexamethylphosphoric triamide; sulphoxides, such as dimethyl sulphoxide.
When carrying out the process (f) according to the invention, the reaction temperatures can be varied within a relatively wide range. In general, the process is carried out at temperatures between 0xc2x0 C. and 100xc2x0 C., preferably between 20xc2x0 C. and 80xc2x0 C.
The process (f) according to the invention is generally carried out under atmospheric pressure. However, it is also possible to carry out the process according to the invention under elevated or reduced pressurexe2x80x94generally between 0.1 bar and 10 bar.
For carrying out the process (f) according to the invention, in general from 1.0 to 3.0 mol, preferably from 1.1 to 2.0 mol, of dichloromethylene-dimethylimmonium chloride of the formula (VII) are employed per mole of starting material of the formula (VI).
In a preferred embodiment of the process (f) according to the invention, the dichloromethylene-dimethylimmonium chloride of the formula (VII) is initially charged in a diluent, and a substituted N-cyanophenyl-aminoalkenamide of the general formula (VI) is added a little at a time with stirring at room temperature (about 20xc2x0 C. to 30xc2x0 C.). The reaction mixture is then stirred at slightly elevated temperature for several hours until evolution of gas has ceased. Work-up can be carried out by customary methods. The mixture is, for example, stirred with aqueous sodium bicarbonate solution and the organic phase is separated off, washed with aqueous sodium bicarbonate solution and then with water and concentrated under reduced pressure. The product that remains in the residue can be crystallized by digestion with an organic solvent (cf. the Preparation Examples).
The process (c) according to the invention for preparing compounds of the general formula (IIa) is carried out using an acid. In this context, preferred acids are protic acids. These include, for example, hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, sulphuric acid, phosphoric acid, methanesulplhonic acid, trifluoromethanesulphonic acid, benzenesulphonic acid, p-toluenesulphonic acid, formic acid, acetic acid, propionic acid and trifluoroacetic acid. Very particular preference is given to using hydrogen chloride as acid in the process (c) according to the invention.
The processes (c) and (d) according to the invention are preferably carried out using diluents. Suitable diluents here are, in addition to water, especially inert organic solvents. These include, in particular, aliphatic, alicyclic or aromatic, optionally halogenated hydrocarbons, such as, for example, benzine, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, petroleum ether, hexane, cyclohexane, dichloromethane, chloroform, carbon tetrachloride; ethers, such as diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran or ethylene glycol dimethyl ether or ethylene glycol diethyl ether; ketones, such as acetone, butanone or methyl isobutyl ketone; carboxylic acids, such as formic acid, acetic acid or propionic acid, nitriles, such as acetonitrile, propionitrile or butyronitrile; amides, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-formanilide, N-methyl-pyrrolidone or hexamethylphosphoric triamide; esters such as methyl acetate or ethyl acetate, sulphoxides, such as dimethyl sulphoxide.
N,N-Dimethylformamide may be mentioned as a particularly preferred diluent for process (c), ethylene glycol dimethyl ether (1,2-dimethoxy-ethane) may be mentioned as a particularly preferred diluent for the processes (d).
When carrying out the processes (c) and (d) according to the invention, the reaction temperatures can in each case be varied within a relatively wide range. In general, the processes are carried out at temperatures between 0xc2x0 C. and 150xc2x0 C., preferably between 10xc2x0 C. and 110xc2x0 C.
The processes (c) and (d) according to the invention are generally carried out under atmospheric pressure. However, it is also possible to carry out the processes (c) and (d) according to the invention under elevated or reduced pressurexe2x80x94generally between 0.1 bar and 10 bar.
For carrying out the process (c) according to the invention, in general from 0.8 to 1.5 mol, preferably from 0.9 to 1.2 mol. of an acid are employed per mole of cyanophenylpyrimidone of the formula (III).
In a preferred embodiment of the process (c) according to the invention, a cyanophenylpyrimidone of the formula (III) is initially charged in a solvent and, at room temperature (about 20xc2x0 C. to 30xc2x0 C.), an acid is slowly metered in. The reaction temperature is then stirred for another few hours and subsequently worked up in a customary manner. The mixture is, for example, poured into ice-water and stirred thoroughly. The product, which is then generally obtained as crystals, can be isolated by filtration with suction (cf. the Preparation Examples).
For carrying out the process (d) according to the invention, in general from 0.8 to 1.5 mol, preferably from 0.9 to 1.2 mol, of an ar(alk)ylamine of the formula (V) are employed per mole of oxazinone of the formula (IV).
In a preferred embodiment of the process (d) according to the invention, an oxazinone of the formula (IV) is mixed with an ar(alk)ylamine of the formula (V) at room temperature in a solvent, and the reaction mixture is stirred at elevated temperature until the reaction has ended. The reaction product is, on cooling, generally obtained as crystals and can be isolated by filtration with suction (cf. the Preparation Examples).
The process (a) according to the invention for preparing compounds of the general formula (I) is preferably carried out using a diluent. Suitable diluents are, especially, inert organic solvents. These include, in particular, aliphatic, alicyclic or aromatic, optionally halogenated hydrocarbons, such as, for example, benzine, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, petroleum ether, hexane, cyclohexane, dichiloromethane, chloroform, carbon tetrachloride; ethers, such as diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran or ethylene glycol dimethyl ether or ethylene glycol diethyl ether; ketones, such as acetone, butanonic or methyl isobutyl ketone; nitriles, such as acetonitrile, propionitrile or butyronitrile; amides, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-formanilide, N-methyl-pyrrolidone or hexamethylphosphoric triamide; esters such as methyl acetate or ethyl acetate, sulphoxides, such as dimethyl sulphoxide.
When carrying out the process (a) according to the invention, the reaction temperatures can be varied within a relatively wide range. In general, the process is carried out at temperatures between 40xc2x0 C. and 120xc2x0 C., preferably between 50xc2x0 C. and 100xc2x0 C.
The process (a) according to the invention is generally carried out under atmospheric pressure. However, it is also possible to carry out the process according to the invention under elevated or reduced pressurexe2x80x94in general between 0.1 bar and 10 bar.
In a preferred embodiment of the process (a) according to the invention, a substituted aminoalkenamide of the general formulae (IIa) or (IIb) is, at room temperature (about 20xc2x0 C. to 30xc2x0 C.), stirred with a diluent, and the mixture is heated with stirring until the reaction has ended. Work-up is then carried out in a customary manner (cf. the Preparation Examples).
The substituted ar(alk)yluracils of the general formula (I) to be prepared according to the invention are already known as herbicidally active compounds (cf. EP-A-648 749).